1. A 10.00 mL aliquot of 0.010 M CaCO3 is titrated with 18.22 mL of EDTA solution. What is the EDTA molarity?
2. A 250.0 mL water sample requires 30.85 mL of the EDTA solution from question 1 to reach the calmagite endpoint. What was the molarity of the hard metal ions in the water sample?
3. If the metal ions in the water sample of question 2 are assumed to be Ca2+ from CaCO3, express the concentration in ppm CaCO3. This is the same as the concentration in units of mg CaCO3 per liter of sample.
1)
moles of CaCO3 = 10 x 0.01 / 1000
= 1.0 x 10^-4 mol
moles of EDTA = moles of CaCO3
moles of EDTA = 1.0 x 10^-4 mol
moles = molarity x volume
1.0 x 10^-4 = molarity x 0.01822
Molarity of EDTA = 5.49 x 10^-3 M
1. A 10.00 mL aliquot of 0.010 M CaCO3 is titrated with 18.22 mL of EDTA...
A titration was performed to standardize an EDTA solution. a) A 25.00 mL aliquot of a standard solution containing 0.01500 M Ca2+ required 42.87 mL of EDTA to reach the endpoint. The molarity of the EDTA solution is: ________ M b) That same EDTA solution was then used to titrate an unknown hard water sample. A 40.00 mL aliquot of unknown hard water required 34.21 mL of EDTA solution to reach a distinct endpoint. The concentration of Ca2+ ions (assuming...
A 50.00 mL aliquot of a hard water sample is titrated with 15.00 mL of 0.01280 M EDTA. A second 50.00 mL aliquot portion is made sufficiently alkaline with NaOH to precipitate the Mg ions. The precipitate was filtered and the filtrate was titrated with 10.00 mL of 0.01280 EDTA. Calculate the ppm Mg and Ca in the water sample.
Please show steps for 32 and 33.
Data Table 1: EDTA Titration Volume Trial Initial EDTA Volume (mL) Final EDTA Volume (mL) Total Volume EDTA Used (mL) 1 9 mL 8.6 mL .3mL 2 8.6 6 2.6 mL 3 6 4.2 1.8mL Average Volume of EDTA Used (mL) 1.6mL Data Table 2: Water Hardness Average Volume of EDTA Used (mL) Concentration Ca2+ lons Per Liter of Water (mol/L) Water Hardness (ppm CaCO3) 1.6mL 32 Using the following equation, determine the...
6. (8) A 50.0 mL sample of hard water containing Ca2 was titrated with 0.0500 M EDTA standard solution at pH 10 and with Eriochrome Black T indicator. The endpoint was reached when 11.35 mL of EDTA was added a) (6) Calculate the concentration of Ca* in the unknown sample in moles per liter (M). b) (2) What is the pCa of the solution?
Name Section Experiment 28 Advance Study Assignment: Determination of the Hardness of Water 1. A 0.3946 g sample of Caco, is dissolved in 12 M HCl and the resulting solution is diluted to 250.0 mL in a volumetric flask. a. How many moles of Caco, are used (formula mass = 100.1)? moles b. What is the molarity of the Ca2+ in the 250 mL of solution? c. How many moles of Caare in a 25.00-mL aliquot of the solution in...
1. Part of a buret measuring in mL is shown below. Read the volume to the proper number of significant digits. Volume mL 2. Suppose it takes 33.69 mL of 0.005123 M EDTA to titrate 25.00 mL of a hard water solution. a) How many moles of EDTA were required to titrate to the endpoint? b) How many moles of hard water ions, expressed as moles of Ca²+, are present in the hard water solution? c) What is the concentration,...
Water Hardness by EDTA Titration Objective: To determine [Ca2+,MG2+] and [Mg2+] concentration in an unknown water sample A 0.0107 molarity solution of EDTA is prepared for the experiment. 25 mL of an unknown is pipetted and diluted 100 mL with distilled water and adjusted to a pH between 8 and 10 with NH4OH. A 10.00 mL portion of the diluted unknown is transferred to a 250 mL flask with 3 mL of pH 10 ammonia buffer and tiny amount of...
A 3.7145-g portion of disodium EDTA dihydrate (M.W. 372.24) was dissolved in enough distilled water to prepare 1.000 liter of solution. A 100.0-mL water sample was adjusted to pH 10 and titrated to endpoint with 11.23 mL of the EDTA solution. Calculate the concentration of the EDTA solution and th e hardness of the water sample. Express the hardness of mg caCO3 /L.
Experiment 9: Water Hardness Pre-Laboratory Questions Name Section 1. Part of a buret measuring in mL is shown below. Read the volume to the proper number of significant digits. Volume 2. Suppose it takes 33.69 mL of 0.005123 M EDTA to titrate 25.00 mL of a hard water solution. a) How many moles of EDTA were required to titrate to the endpoint? b) How many moles of hard water ions, expressed as moles of Ca?", are present in the hard...
Hard water normally contains mineral ions, such as Ca2+ and Mg2+ ions, from minerals that dissolved in the ground water. For water of low hardness, the concentration of Ca2+ ions is usually expressed as ppm CaCO3 in the water sample. Parts per million (ppm) is defined as one part of solute mass per 1,000,000 parts of solution mass, as shown in the following equation. Please note, the unit of denominator and numerator needs to be the same. Since ppm expresses...